WASHINGTON — The government says water tests have confirmed underwater oil plumes from the BP oil spill, but that concentrations are “very low.”

NOAA Administrator Jane Lubchenco said that the tests conducted at three sites by a University of South Florida research vessel confirmed oil as far as 3,300 feet below the surface 42 miles northeast of the well site. Oil also was found in a sub-surface sample 142 miles southeast of the spill, but further tests showed that oil is “not consistent” with oil from the spill.

Lubchenco said the water analysis “indicate there is definitely oil sub surface. It’s in very low concentrations” of less than 0.5 parts per million. Additional samples from another research vessel are being tested, she said.

“We remain concerned about the location of oil on the surface and under the sea,” said Lubchenco.